Prior Art
The ball bearing is now widely used in mechanics, and used to provide a steady and fast operation. The ball bearing combined with a screw rod has a preferred effect. In the prior art, the screw is combined with a cover seat. Since the rotation of the screw rod is purely along the thread, the rotary speed cannot gain a preferred convenience. This is because the thread is very active in movement of the screw rod, especially, as the screw rod and the cover se at have become rusty.
As a consequence, a ball bearing arrangement was invented. Referring to FIG. 1, the ball bearing seat (A) covers a screw rod (B). The balls will roll within the ball bearing seat (A), thus the screw rod can be operated quickly. This kind of structure is widely employed today. However, it has been known that there are some defects in using that type of ball bearing. That is, in order that the balls (C) may roll within the ball bearing seat (A), a guiding tube (A1) is installed outside the bearing seat, so that the balls (C) may roll cyclically within the ball bearing seat (A) and through the guiding tube (A1). But, since the guiding tube (A1) is installed outside the bearing seat, in operation, the ball bearing seat (A) will vibrate eccentrically. Thus in design, the ball bearing seat (A) is eccentric with respect to the installation of the guiding tube, so that the bearing seat will not rotate with equilibrium. In installing the guiding tube (A1), the guiding tube covers on one side of the ball bearing seat (A), thus during installation, it is difficult to assemble with the balls (C) and a fixing piece (A2) that is used to fix the guiding tube (A1). Therefore, the possibility of loosening of the fixing screws increases. Further, since the weights of the parts are not identical, the structure will not be steady.